Cameron Keng
, ContributorI cover a lot of taxes and even more about business.Opinions expressed by Forbes Contributors are their own.

Small Biz Saturday is a series where we help scrappy entrepreneurs or fledgling entrepreneurs discover new opportunities to earn more. We’re looking to get to the brass tacks and nitty-gritty. We want to look under the hood to learn the details that help us do it ourselves. We’re going to look at the numbers so that we know exactly how this is going to put more money in our pockets.

Everyone has heard about Airbnb. It’s the elephant in the room, everyone hears stories about how they can earn supplemental income by renting or selling the extra room in their home. I’ve always heard that it’s profitable, but what does that really mean in dollars and cents.

There are two ways to look at Airbnb. (1) It’s a way to help make ends meet by lowering the cost of your mortgage or rent. We’re not going to examine Airbnb in this lens because it’s not a business that we can earn and live off, but it is a reasonable way to help save so that you can one day start a business. (2) Airbnb is a business where every dollar and minute we spend is a cost that we invest to make a profit that we can consistently repeat for years.

If you’re looking to start a business focused on Airbnb, you’re basically operating a hotel for all intents and purposes. The single most important number you’re going to need to focus on and understand is “occupancy rate.” Occupancy rate is the frequency that you rent your space. If there are 100 days available for you to rent out and you only rent 50 days. Your occupancy rate is 50%. The national occupancy rate is 65.8% in 2016. This is a safe number to use as an assumption for your apartment if you do everything right on average.

Selecting an accurate occupancy rate is important to help you determine your rental prices and whether you’ll be able to make a profit. Personally, whenever I make projections I would underestimate the revenues and overestimate the expenses. Better safe, then sorry.

The main expenses you’ll need to expect are rent or property taxes and maintenance, cleaning, utility, internet and commission fees. But, most people forget to take into consideration taxes. Taxes are going to be more than you think. You’ll need to assume at least 20% of the “profit” you earn will be “income taxes.” Now there is another tax that you’ll need to know about – self-employment taxes. Self-employment taxes are 15.3%. Thus, taxes are going to be 35.3%.

Assuming all the above, this is what the financials for your Airbnb look based on the national average: